originTrump is the best argument against a democracy.Valued Senior Member

I assumed Newton meant space without motion or matter and time was so subtle to notice it passes by at an immediate rate?

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Newton assumed that time was absolute and he had no reason to believe it was not.
Around 1900 it was found that the speed of light in a vacuum was constant, independent of the motion of the observer or the source.
That led to relativity and the concept of time dilation.

In Newtons time the speed of light was not known, it was not even known if light traveled instantaneously from source to observer.

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Yes, it was too quick by some of my co-contributors, and I am not judging you yet. But as I'm a chemist who only understands Special Relativity on a good day, and General Relativity barely at all, only its effects, I'll leave others to field your questions.

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Newton assumed that time was absolute and he had no reason to believe it was not.
Around 1900 it was found that the speed of light in a vacuum was constant, independent of the motion of the observer or the source.
That led to relativity and the concept of time dilation.

In Newtons time the speed of light was not known, it was not even known if light traveled instantaneously from source to observer.

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I am at loss to how you have answered my question or how the speed of light constant has anything to do with time passing by?

Hello all, my daughter has asked me about some school work she has to do, the topic is time dilation. I have looked and youtube but did not understand it, could somebody please explain how time can slow down?

It sounds a bit strange to me.

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My understanding is that:

Time Dilation is not slowing down of time but it is the slowing down of a clock. As the gravity becomes stronger, movement of clock becomes slower. Here time is as indicated by a clock.

I am at loss to how you have answered my question or how the speed of light constant has anything to do with time passing by?

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You do realize that speed has two components to it, right? Distance & time. (Miles per hour, feet per second, furlongs per fortnight, etc...) If everyone measures light at the same speed, independent of the motion of the observer or the source, then something funny must be going on with distance and/or time.

The root of relativity is the observation that the measured speed of light does not depend on the motion of the emitting source relative to the detecting observer. This was totally counterintuitive and unlike any "normal" wave, which propagates at a fixed speed in a medium (e.g. water waves, sound waves), so that if the emitter or receiver moves in the medium the apparent speed of the waves, as seen from each viewpoint, alters. However, in fact, James Clerk Maxwell's mathematical description of light had already predicted that light waves did not need a medium. So physicists knew there was trouble brewing. The classic experiment was this one: https://en.wikipedia.org/wiki/Michelson–Morley_experiment

Various people, of whom Einstein was one, tried to work out how this could be and what the implications were. One of them was that, if light speed was measured the same by both emitter and receiver, irrespective of their motion, then length and time could not be fixed, since the only way to get speed (=distance/time) constant would be if both length and time themselves altered (yikes!), depending on the relative motion between the emitter and receiver.

All the rest then followed.

But, as I said before, if you are a normal person you will need to read about this several times, slowly and carefully, with a wet towel wrapped round your head, before you get it. It is very very counterintuitive indeed. But it seems to be true, since many, many observations have confirmed it.

You do realize that speed has two components to it, right? Distance & time. (Miles per hour, feet per second, furlongs per fortnight, etc...) If everyone measures light at the same speed, independent of the motion of the observer or the source, then something funny must be going on with distance and/or time.

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This is the greatest answer actually, this directly leads to length contraction and time dilation. Qualitatively constancy can be satisfied with length elongation and time contraction, but length cannot elongate.

You do realize that speed has two components to it, right? Distance & time. (Miles per hour, feet per second, furlongs per fortnight, etc...) If everyone measures light at the same speed, independent of the motion of the observer or the source, then something funny must be going on with distance and/or time.

The root of relativity is the observation that the measured speed of light does not depend on the motion of the emitting source relative to the detecting observer. This was totally counterintuitive and unlike any "normal" wave, which propagates at a fixed speed in a medium (e.g. water waves, sound waves), so that if the emitter or receiver moves in the medium the apparent speed of the waves, as seen from each viewpoint, alters. However, in fact, James Clerk Maxwell's mathematical description of light had already predicted that light waves did not need a medium. So physicists knew there was trouble brewing. The classic experiment was this one: https://en.wikipedia.org/wiki/Michelson–Morley_experiment

Various people, of whom Einstein was one, tried to work out how this could be and what the implications were. One of them was that, if light speed was irrespective of speed of emitter and receiver, then length and time could not be fixed, since the only way to get speed (=distance/time) constant would be if both length and time themselves altered (yikes!), depending on the relative motion between the emitter and receiver.

All the rest then followed.

But, as I said before, if you are a normal person you will need to read about this several times, slowly and carefully, with a wet towel wrapped round your head, before you get it. It is very very counterintuitive indeed. But it seems to be true, since many, many observations have confirmed it.

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You are seemingly going off the topic of time and keep mentioning the speed of light , which is defined by d/t, time and distance being independent of a photon.